Answer:   AutoPostBack is a property which is used to postback automatically when an event is raised. You have to set the AutoPostBack property of the control to True.

Answer:   Autopostback is the mechanism by which the page will be posted back to the server automatically based on some events in the web controls. In some of the web controls, the property called auto post back, if set to true, will send the request to the server when an event happens in the control.